As an example, let's see how a radio receiver works with such batteries.
Tools and materials:
-Empty tin can;
-Wires with “crocodiles”; Step one: general description
Below you can see the parameters of the battery made from one tin can.
170 mA (no load)
Charging time: 2 minutes when using a power bank. (5V, 2A)
Examples of battery operation of devices:
Four mini motors for 30 minutes.
LED garden lamp – 3 hours
Flashlight for 20 minutes (Flashlight requires only one AA battery to work.
The batteries have already been recharged 10 times and will need to replace the aluminum foil in the near future.
Six 820mm cans installed in series were able to power a small radio for 20 minutes.
Batteries have a high self-discharge rate and cannot be stored for long.
Step two: saline
Pour a cup of hot salted water into the container.
Add salt to the water until it stops dissolving. Let the solution cool.
Step three: assembly/impregnation
Cut out a sheet of A4 paper so that it wraps around the can. Wrap the sheet and glue the seam. Place the jar in a container of saline and soak the paper well.
After impregnation, apply PVA glue on top of the paper. You need to cover the entire surface of the paper.
After 20 minutes, when the glue dries, you need to wrap the jar with a second sheet of paper. Then glue the joint and soak the paper with saline.
The last paper layer is a paper towel. It is not necessary to apply PVA glue between it and the paper, but it is necessary to soak it with a saline solution. A towel is optional, but it prevents the battery from drying out.
Step four: foil
Now you need to wrap the can in foil.
Fold a sheet of aluminum foil in half to make a double layer. Wrap the foil around the can (be careful not to let the foil touch the metal can).
Break off a little of the winding at the top so that you can attach a clip to the jar.
The bottom of the can should also be wrapped with foil, but so that it touches the main foil, but does not touch the can. The second clip must be connected to the foil.
Step five: charging
The master used a power bank to charge the battery. You need to cut off the end of the USB cable. There are four insulated conductors on the cable. Two wires for data, two for power supply. By connecting one power wire to the jar and the other to the foil, you can charge the battery. The positive wire connects to the jar, the negative to the aluminum foil.
In principle, any power source up to 12 volts is suitable for charging. Charging time is about 2-3 minutes.
After charging, you can check the voltage with a voltmeter.
As mentioned earlier, the battery can power various low-consumption devices for a short time. A circuit known as a joule thief can be used to increase the voltage. You can make it yourself or dismantle it, for example, from a solar-powered garden lamp.